ThermoGen will develop an in vivo protein engineering system allowing rapid, random shuffling of protein domains to produce novel proteins formed by gene fusion. This system will be designed to allow general production of chimeric genes with altered functions, mapping of functional domains in a target protein, and construction of random linker insertions to probe protein structure. Phase I will show feasibility of the project by constructing two transposon elements, one for creating amino and carboxy domain fusions with any gene, and another for inserting linker sequences into a gene to map its structure. To test this system, Protein A fusions with Thermo-beta-galactosidase (Tbg) will be made and compared for their thermostability and activity for use in immuno-labelling experiments. Linker insertions into big will be constructed and characterized to functionally map the Tbg structure. Phase II will involve refinement of the in vivo system allowing random domain insertion, further characterization of the tbg products, and as well as extension of the system to several other commercially and medically interesting fusion products. Phase III will involve marketing of these fusion products or licensing and contracting work with the in vivo fusion system, or packaging it as a kit for general use.